Welcome to the website of Swimming Human Simulation Model "SWUM"!

Last update : 2014/8/15

What is SWUM?

SWUM (SWimming hUman Model) is a Swimming Human Simulation Model,
which has been developed as a powerful analysis tool for
various dynamical problems in human swimming.
In SWUM, the absolute motion of the whole human body is
solved from the equations of motions for the fluid force
and the body inertia,
by giving the relative body motion (joint angles).
SWUM enables you to analyze the various dynamical problems in swimming,
such as the effect of difference of the swimming form
on the swimming speed and the absolute body motion.

By Whom?

Analysis Example

Below movies are analysis examples of SWUM
for the four modern strokes,
which show the motions for one cycle in steady state.
The red lines show the fluid force acting on the each part of the body.
The water surface is checkered.
The total width of the dark and pale blue area corresponds
to the stroke length (swimming distance during one cycle).
The front crawl, breast, back and butterfly strokes are in order below.
(Please use your viewer software's repeat playing function,
since the movie is for only one cycle.)

Free Software "Swumsuit" as SWUM's Implementation

A software "Swumsuit" was developed
as an implementation of the ideal model SWUM.
In addition,
Swumsuit enables everyone to perform simulation
of the human swimming
with easy GUI (Graphical User Interface) operation.
Swumsuit is a Free Software based on GPL (GNU General Public License).
For the detail of Swumsuit,
please see Swimming Human Simulation Software Swumsuit page.

Musculoskeletal Simulation

By Swumsuit version 3.0.0 or higher,
you can output files for the musculoskeletal analysis software
"AnyBody Modeling System".
By using Swumsuit and AnyBody Modeling System,
you can conduct the full-body musculoskeletal simulation for swimming.
Simulation examples for the four strokes are shown as below.

Analysis of Top Swimmer's Underwater Dolphin Kick

The mechanism of the underwater dolphin kick has been analyzed by SWUM.
After the analysis of the dolphin kick by a top athlete swimmer,
optimizating calculations to maximize the swimming speed and propulsive efficiency
were conducted.
The details are in the Reference 6 below.

Simulation of Dive Start

The dive start has also been simulated by SWUM.
For this simulation, a special fluid force which acts on the body during water entry
has been introduced to SWUM.
The details are in the Reference 7 below.

"Multi Agent/Object Simulation"

By Swumsuit 4.0.0 or higher, the "Multi Agent/Object Simulation" has been enabled.
"Multi Agent/Object" means multiple swimmers, such as synchronized swimming, and multiple objects
with a swimmer, such as equipment in the water.
The below examples are monofin swimming (swimmer + monofin),
the shooting motion in the water polo, and the lift in the sychronized swimming.
The details are in the References 8, 9 and 13 below.

Application to Walking in Water

SWUM has also been applied into the walking in water,
which is very effective for rehabilitation.
In this analysis, the ground reaction force acts on the foot
in addition to the fluid forces.
The details are in the Reference 10 and 11 below.

Keiko Akiyama, Motomu Nakashima and Issei Ogasawara,
Proposal of Walking in Water for ACL Injury Rehabilitation Program by Simulation
Journal of Biomechanical Science and Engineering, Vol.5, No.4 (2010), pp.461-471
(Download full paper at the journal's website)